Simultaneous detection of mixed pesticide residues based on portable Raman spectrometer and Au@Ag nanoparticles SERS substrate

A label-free SERS sensor was successfully developed for simultaneous detection of acetamiprid and thiram using easily synthesized bimetallic core-shell Au@Ag nanoparticles. Au@Ag nanoparticles synthesized by a seed-mediated growth method were used as SERS substrates to realize simultaneous detection of mixed pesticides according to the SERS intensity at 635 (acetamiprid) and 1385 (thiram) cm-1. Complex mixed pesticide systems were established to research the feasibility of simultaneous detection of this SERS sensor. The method showed satisfactory linearity in the range of 5-100 & mu;M and 0.5-10 & mu;M with the limit of detection of 1.22 & mu;M and 0.076 & mu;M for acetamiprid and thiram in apple juice samples, respectively. The recovery for accuracy and precision analysis was 90.2-122.12% in apple juice samples. This SERS detection method combined with portable Raman spectrometer will become a powerful tool for simultaneous testing of multiple contaminants in food safety on-site detection.